Adjustable cam having readily detachable indexing means



June 1967 J. E. WOOLDRIDGE ETAL 3,325,610

' ADJ USTABLE CAM HAVING READILY DETACHABLE INDEXING MEANS INVENTORS JAMES E. WOOLDWDGE OSCAR A.WURTENBERG Filed Aug. 23, 1965 ATTORNEY United States Patent 3,325,610 ADJUSTABLE CAM HAVING READILY DETACHABLE INDEXING MEANS James E. Wooldridge and Oscar A. Wurtenberg, Louisville, Ky., assiguors to Continental Air Filters, Inc.,

Louisville, Ky., a corporation of Delaware Filed Aug. 23, 1965, Ser. No. 481,836 Claims. (Cl. 200-38) This invention relates to adjustable cams, and to a timing circuit employing the same, and more particularly to such a cam having a readily detectable indexing means incorporated on the face of the cam.

The use of adjustable cams having a pair of cooperating discs which are relatively adjustable angularly of the shaft on which they are mounted, is Well known. Generally, such a cam is selectively set or indexed by aligning an index on one of the cam discs, such as an edge of a recess in that disc, with respect to an index on the other cam disc, such as one of a series of scribed lines on that other disc. In order to secure an accurate cam setting in such a combination a slow and careful positioning of the discs must be followed, and when the cam ismounted in a poorly illuminated or inaccessible location, the chance of error in the setting is greatly increased. In particular, when percentile settings of the cam in order to produce a desired on-off cycle of a circuit controlled by the cam is required, the operator is compelled to exercise special care in indexing that cam.

It is these and other disadvantages found in adjustable cams of the conventional type which the present invention is intended to overcome.

An object of the invention is to provide a simple adjustable cam structure having a pair of relatively movable cam discs jointly incorporating a readily detectable indexing means.

Another object is to provide an adjustable cam incorporating an indexing means presenting to the operator conveniently arranged indicia showing percentile settings of an on-oif cycle of equipment controlled by the cam setting.

Another object is to provide a timing system controlled by an adjustable cam and incorporating an illuminating means to increase the accuracy of the setting of the cam parts.

Other objects and advantages of the invention will become apparent as the description proceeds and when considered in conjunction with the accompanying drawings in which:

FIG. 1 is a front elevation view of a timing assembly structure employing the adjustable cam.

FIG. 2 is a side elevation of the structure shown in FIG. 1.

FIG. 3 is a detail view to a larger scale showing a fragmentary portion of the face of one of the cam discs, and

FIG. 4 is a diagrammatic view of a wiring circuit for the timing assembly employing the adjustable cam.

The adjustable cam of the invention may be employed for any conventional usage made of cams, but by way of illustration and not of limitation is disclosed herein in connection with an electrical timing assembly. As best shown in FIGS. 1 and 2, such an assembly includes a compact structure embodying a bracket adapted to be mounted upon associated structure (not shown) and within reach of the operator. This bracket includes a face plate having a central aperture or window 11 therein and with this aperture preferably being covered by a sheet 12 of translucent material. A laterally disposed mounting flange 13 with mounting holes 14 therein is Patented June 13, 1967 offset from the face plate by a wall 15 to give depth to the bracket.

Mounted upon the visible face plate of the bracket is a micro switch 16 having a cam follower 17 extending therefrom, and mounted upon the rear face of the bracket is a light source, such as a small incandescent bulb 18. A timing motor 19 is mounted upon the rear of the bracket and includes a shaft 20 extending through an aperture in the face plate 10 and to which the adjustable cam, now to be described, is suitably attached.

The composite adjustable cam includes a second cam disc having a generally circular peripheral edge 26 which is interrupted by a notch having a configuration which embodies a chief feature of the present invention. This notch which preferably embraces an angle of about has a leading edge 27 which is straight and which extends between the peripheral edge 26 and the bottom 28 of the notch. The bottom 28 is concentric with the axis of shaft 20. The trailing edge of the notch is serrated and includes a series of straight sighting edges 30, 31, 32, 33, 34, and 36 each of which is located on a radius of the cam disc 25 and is displaced angularly at equal distances from the adjacent such edge. The intervening ledges 30A to 35A are concentric with the axis of shaft 20. Concentric indicia, such as indicated at 37, 38, 39 and 40, are arranged on the face of that cam disc as extensions of the ledges. The outermost radial edge 41 is suitably rounded at its junction with the peripheral edge 26 of the cam disc and extending between edges 30 and 41 is an uppermost ledge 41A which likewise is concentric with the axis of shaft 20.

The cam disc 25 is provided with a hole at its center into which the shaft 20 extends. The outer end of the shaft is threaded and engages with a threaded adjusting knob 42 which bears at all times upon a securnig means 43, such as a spring, which is interposed between the knob and the external face of disc 25.

For cooperation with the above-described cam disc 25, a first cam disc having a collar 51 embracing shaft 20 and disposed between the face plate 10 and the second cam disc, is employed. By means of a set screw, not shown, the collar is rigidly afiixed to that shaft. The peripheral edge 52 of the first cam disc is generally circular and has a radius corresponding to that of the second cam disc, and is interrupted by a notch having a1eading sighting edge 53. This sighting edge is straight, except for a slight rounding at its junction with the peripheral edge 52, lies in a radius of the first cam disc 50, and extends toward the center of the cam disc 50 at least as far as the location of bottom 28 in the notch of the second cam disc 25. The shape and location of the trailing edges of the notch in the first cam disc 50 is immaterial, except that the angle embraced between these leading and trailing edges of that notch is at least as great as the angle embraced by the corresponding notch edges in the second cam disc.

An adjustable cam of the described construction may be used for many control purposes, but in connection with the present invention we incorporate the same in an improved timing assembly as diagrammatically shown in FIG. 4. In this arrangement power is supplied to timing motor 19 by conductor through a closed switch 61 and return conductor 62, and a shunt circuit 63 energizes lamp 18. The microswitch 16, when closed by its follower riding on the joint peripheries 26 and 52 of the cam discs, energizes a relay 64 which controls a separate circuit leading to the apparatus whose timed cycle of operation is to be governed.

With the foregoing in mind, the following description of an adjustment of the cam will indicate the several advantages of the invention. Assuming that the circuit controlled by relay 64- is to be held open for a period corresponding to 6% of the time it takes for a revolution of motor driven shaft 20, the operator opens switch 51 leaving light 18 illuminated and shining through the translucent window 11 and through the notches in the two cam discs. As shaft 20 comes to rest the leading edge 53 of the notch of the first disc is distinctly visible to an operator positioned in front of the cam. Thereupon, the knob 42 is loosened and the second cam disc 25 is slowly turned until the sighting edge 34 coincides with edge 53 as indicated by the interruption of light between those respective edges; the knob is then re-tightened to cause spring 43 to compress and to impose a substantial frictional contact between the confronting faces of the two cam discs sufiicient to lock the two parts together. Reclosing of switch 61 then restarts motor 19.

It is not essential to employ the light 18 in certain cases where the operator has close visual access to the cam. In such instances an equivalent accurate setting may be achieved by using a feeler gauge to insure that no space is present between the straight edges being aligned. Also in certain cases the feeler gauge could be used where the operator does not even see the cam.

The combination of a conventional timing circuit and the improved adjustable cam is conveniently employed with a bracket such as shown. Such a bracket with the parts mounted thereon can easily be attached to stationary structure at any point within reach of the operator.

While preferred embodiments of the invention have i been illustrated and described, the scope of the invention,

however, is defined by the following claims.

What is claimed is:

1. An adjustable cam comprising first and second cam discs mounted upon a common axial shaft, said first disc being secured upon said shaft to rotate therewith and having a notch on its periphery including a straight leading edge extending radially toward the axis of said shaft, said second disc being adjustably mounted on said shaft and having a notch on its periphery including a serrated trailing edge; said serrated edge comprising a series of radially disposed straight portions successively displaced angularly of said second disc and separated by ledge portions located on different radial distances from the axis of said shaft, the notch in said first disc embracing an angle at least as great as that of the notch in said second disc whereby said second disc may be adjusted to bring the straight radial portion of any selected serr-ation thereof into alignment with the leading edge of said first disc,

and means for holding said second disc in fixed position with respect to said first disc following said alignment of the respective discs.

2. An adjustable cam as defined in claim 1 wherein said ledge portions are concentric with respect to the axis of said shaft.

3. An adjustable cam as defined in claim 2 wherein said second disc bears arcuately disposed indicia on its front face arranged as extensions of said ledge portions.

4. An adjustable cam as defined in claim 1 wherein said second disc is mounted in front of said first disc.

5. In a timing assembly the combination comprising, a bracket having a window therein, a timing motor mounted on the rear of said bracket and having a shaft projecting from the front of said bracket, a timing cam mounted upon said shaft at the front of said bracket, a light source mounted on the rear of said bracket and adapted to pass light rays through said window, a relay for controlling a separate circuit, a switch mounted upon said bracket for controlling said relay, a source of electrical power connected to said motor, said light, said light and said switch; and a cam follower disposed forwardly of said bracket and cooperating with said cam to open and close the circuit through said switch, said cam having first and second cam discs mounted upon said shaft, said first disc being secured to said shaft and having a notch on its periphery including a straight leading edge extending radially toward the axis of said shaft, said second disc being adjustably mounted on said shaft and having a notch on its periphery including a serrated trailing edge, said serrated edge comprising a series of radially disposed straight portions successively displaced angularly of said second disc, the notch in said first disc embracing an angle at least as great as that of the notch in said second disc and each of said notches being disposed forwardly of said window, whereby the second disc may be adjusted to bring the straight portion of any selected serration thereof into alignment with the leading edge of the notch in said first disc as shown by the interruption of light rays between the same, and means for holding said second disc in fixed position with respect to said first disc following said alignment.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

H. E. SPRINGBORN, Assistant Examiner. 

1. AN ADJUSTABLE CAM COMPRISING FIRST AND SECOND CAM DISCS MOUNTED UPON A COMMON AXIAL SHAFT, SAID FIRST DISC BEING SECURED UPON SAID SHAFT TO ROTATE THEREWITH AND HAVING A NOTCH ON ITS PERIPHERY INCLUDING A STRAIGHT LEADING EDGE EXTENDING RADIALLY TOWARD THE AXIS OF SAID SHAFT, SAID SECOND DISC BEING ADJUSTABLY MOUNTED ON SAID SHAFT AND HAVING A NOTCH ON ITS PERIPHERY INCLUDING A SERRATED TRAILING EDGE; SAID SERRATED EDGE COMPRISING A SERIES OF RADIALLY DISPOSED STRAIGHT PORTIONS SUCCESSIVELY DISPLACED ANGULARLY OF SAID SECOND DISC AND SEPARATED BY LEDGE PORTIONS LOCATED ON DIFFERENT RADIAL DISTANCES FROM THE AXIS OF SAID SHAFT, THE NOTCH IN SAID FIRST DISC EMBRACING AN ANGLE AT LEAST AS GREAT AS THAT OF THE NOTCH IN SAID SECOND DISC WHEREBY SAID SECOND DISC MAY BE ADJUSTED TO BRING THE STRAIGHT RADIAL PORTION OF ANY SELECTED SERRATION THEREOF INTO ALIGNMENT WITH THE LEADING EDGE OF SAID FIRST DISC, AND MEANS FOR HOLDING SAID SECOND DISC IN FIXED POSITION WITH RESPECT TO SAID FIRST DISC FOLLOWING SAID ALIGNMENT OF THE RESPECTIVE DISCS. 